Measurements of two-photon excitation (TPE) cross sections of fluorescein, rhodamine B and DiI were extended to 1050 nm. TPE cross sections of various Ca2+ indicators, such as calcium green, calcium orange, Fura-2, fluo-3 and etc., were systematicly investigated from 700 to 910 nm. The TPE spectra are identical for the free and Ca2+ bound forms of Ca-Crimson, Ca-Orange and Ca-Green-1. The ratios of fluorescence intensity for the Ca-free to Ca-bound forms of these indicators are also comparable to their reported one-photon values.